Fair value measurement - Narrative (Details)	3 Months Ended	12 Months Ended
	Sep. 30, 2023 USD ($)	Dec. 31, 2024 USD ($) Investment	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset impairment charges		$ 1,097,000	$ 3,359,000	$ (323,000)
Future funding commitments		100,000	700,000
Unfunded commitments related funds		0
Level 2 | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of total long-term debt		$ 2,980,000,000	2,930,000,000
Fair Value Measured at Net Asset Value Per Share | Defined Benefit Plan, Common Collective Trust | Retirement Plans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of investments held in collective trusts | Investment		5
Fair Value Measured at Net Asset Value Per Share | Common collective trust - fixed income | Retirement Plans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of investments held in collective trusts | Investment		4
One Investment | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments, impairment loss				$ 2,500,000
MadHive Inc
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
After-tax gain on sale of equity method investment	$ 25,800,000		$ 25,800,000